Turkish telecom company Turkcell has dropped its multibillion-dollar US lawsuit against rival African mobile phone group MTN Group, citing a recent US Supreme Court ruling that hurt its case.

Turkey's largest cell phone operator filed a $4.2 billion lawsuit in Washington last year alleging the Johannesburg-based company used bribery to win a mobile license in Iran that was first awarded to Turkcell.

But the court delayed the case in October pending a US Supreme Court decision on the Alien Tort Statute, the US human rights law on which Turkcell's suit is based.

In April, the high court limited the ability of foreign plaintiffs to invoke the 200-year old law without a strong US connection to the conduct.

In a Wednesday filing, lawyers for Turkcell asked to dismiss the case in light of the Supreme Court ruling.

The move from Turkcell to drop the case, though, also comes after an external committee appointed by MTN has found the allegations to be false.

MTN, which has a market value of $34 billion, has operations in 22 countries across Africa and the Middle East.